/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.filesystem.stream;

import java.util.HashSet;
import java.util.Set;
import java.util.TreeMap;

/**
 * Track the upstream tasks to determine whether all the upstream data of a checkpoint
 * has been received.
 */
public class TaskTracker {

	private final int numberOfTasks;

	/**
	 * Checkpoint id to notified tasks.
	 */
	private final TreeMap<Long, Set<Integer>> notifiedTasks = new TreeMap<>();

	public TaskTracker(int numberOfTasks) {
		this.numberOfTasks = numberOfTasks;
	}

	/**
	 * @return true, if this checkpoint id need be committed.
	 */
	public boolean add(long checkpointId, int task) {
		Set<Integer> tasks = notifiedTasks.computeIfAbsent(checkpointId, (k) -> new HashSet<>());
		tasks.add(task);
		if (tasks.size() == numberOfTasks) {
			notifiedTasks.headMap(checkpointId, true).clear();
			return true;
		}
		return false;
	}
}
